Conventionally, a mounting structure of a grounding terminal on a printed circuit board for grounding the printed circuit board, in which a grounding terminal is mounted on the surface of the printed circuit board and pressed against a grounding conductor, is known. FIG. 5 is a plan view of such a conventional grounding structure and FIG. 6 is a longitudinal sectional view along line VI--VI of FIG. 5. As shown in FIG. 6, the grounding terminal 100 is soldered to the conductive pattern 201 on the printed circuit board 200 with solder 202. Then, the grounding terminal 100 is pressed against the grounding conductor, thereby grounding the printed circuit board 200. To illustrate the structure simply, the grounding conductor 300 is not shown in FIG 5.
The grounding terminal 100 is formed by bending a strip-like thin sheet metal member with a width of .alpha., for example, 0.8 mm, and has a joint part 101 with a longitudinal length of .beta., for example, 3.5 mm. One surface of the joint part 101 is a joint surface 101a which is soldered to the conductive pattern 201 on the printed circuit board 200. Also, the grounding terminal has a contact part 102 which adjoins the joint part 101 and is bent in the upper direction. An outer surface 102a of the contact part 102 is pressed against the grounding conductor 300. As the result of load by the grounding conductor, the contact part 102 is elastically deformed around the bending area .gamma., and is pressed against the grounding conductor 300 by restoring force caused by the elastic deformation, thereby electrically connecting the printed circuit board 200 and the grounding conductor 300 properly,
When the aforementioned grounding terminal is soldered to the printed circuit board, reflow soldering is usually employed. Reflow soldering comprises the steps of previously applying a suitable amount of solder to the point to be jointed, fixing the grounding terminal to the point temporarily, and melting the solder by using an external heat source, and all these steps are performed automatically. An advantage of reflow soldering is that by allowing a suitable amount of solder to be applied, it prevents solder from being placed at inappropriate points of the printed circuit board, and thus prevents improper soldering such as a defective bridge. Also, there is another advantage that in the case where a relatively small mounting member as aforementioned is to be mounted, self-alignment effect can be expected That is, even if the temporarily fixed member deviates a little from the conductive pattern of the printed circuit board, the member is moved to the right position by surface tension of the melted solder.
However, there are the following problems in reflow soldering of the above conventional grounding terminal
(1) The grounding terminal 100 is moved to the right position by self-alignment effect by surface tension of the melted solder, and then is finally positioned by hardening of the melted solder. During the hardening process of the solder, the grounding terminal 100 sometimes deviates from the right position on the printed circuit board 200 because of, for example, vibration. This results from the fact that since the amount of the solder is large, the thermal capacity of the solder is large, and thus it takes time for the solder to harden If the grounding terminal 100 deviates from the right position, the contact part 102 may not be pressed against the grounding conductor 300 in an appropriate state. Furthermore, the requirements of highly precise mounting performance for allowing high density mounting are not satisfied PA1 (2) When the temperature of the grounding terminal 100 reaches the melting point of the solder earlier than that of the conductive pattern 201 of the printed circuit board 200, what is called wicking phenomenon occurs, by which the solder 202 is sucked up along the bending area .gamma. forming the center of elastic deformation of the contact part 102 shown in FIG. 6. In this case, since the solder 202 adheres around the bending area .gamma., the elastic deformation performance of the contact part 102 is lowered, and thus it is sometimes impossible to attain elastic deformation enough for the contact part 102 to be pressed against the grounding conductor 300 and conduct electricity to the grounding conductor 300.